SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f673d6f8bd497fff3b5a90b8557cf06644f970cb2eba1509ee4172866fcc65ea' 
  AND token = '5tKHLhp/NnO7xJmTTdSPvvrgFnqsPFbBbIw+zaakhtI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}